The Integrated Circuit (IC) card, especially the contactless IC card, after over ten years' development, has been widely applied in fields such as public transport, entrance guard, and petty electronic payment etc. At the meantime, the mobile terminal has been popularized among residents after rapid development of over twenty years, and offers great convenience for people's work and life. The mobile terminal has more and more powerful functions, and has a tendency to incorporate more functions. The combination of the mobile terminal with the contactless IC card technique enables the mobile terminal to be applied in the electronic payment field, which will further extend the application scope of the mobile terminal and offer more convenience for people's life, and has a vast application prospect.
At present, the eNFC is a mainstream mobile payment solution in China, and obtains supports of operators and related terminal manufactures. The eNFC technique is an enhancement and improvement of the Near Field Communication (NFC) technique. It is a short distance wireless communication technique working at 13.56 MHz, and is evolved from the convergence of the Radio Frequency Identification (RFID) technique and interconnection technique. After applying the eNFC technique, the mobile terminal can emulate a contactless IC card for use in applications related to electronic payment.
To apply the eNFC technique on a mobile terminal, it is required to add a NFC emulation front end chip, Contactless Front-end (CLF), and a NFC antenna on the mobile terminal, and further to use a mobile user card supporting the Single Wire Protocol (SWP), which can be a Subscriber Identity Module (SIM) card, a User Identity Module (UIM) card, or a User Service Identity Module (USIM) card etc. The RFID protocols supported by the NFC emulation front end chip include ISO 14443 Type A/Type B, Felica, and ISO15693 etc.
The NFC emulation front end chip can communicate with the main processor of the mobile terminal through a Universal Asynchronous Receiver/Transmitter (UART) interface; the NFC emulation front end chip connects with the C6 pin of the mobile user card through a signal line, and communicates with the application part in the mobile user card by using the SWP; the mobile user card connects with the main processor chip of the mobile terminal through an ISO7816 interface, and this connection uses the Reset, CLK, and IO pins of the mobile user card, which can correspond to the C2, C3 and C7 pins respectively.
The feature of the eNFC is that the application related to electronic payment is stored in the mobile user card and the storage and execution of the electronic payment is carried out by the mobile user card. Besides, the VCC, namely the C1, pin of the mobile user card is connected with the NFC emulation front end chip so that the eNFC technique is able to support the terminal power down mode. In this mode, the NFC emulation front end chip and the mobile user card obtain energy from an electromagnetic field generated by an external contactless card reader via the NFC antenna, and thus can also work in a card emulation mode when the mobile terminal is power off, and interact with the external contactless card reader to complete the electronic payment.
After applying the eNFC technique, the mobile terminal can support three different working modes according to different application scenarios, which are respectively a card emulation mode, a card reader mode and a point to point mode. In the card emulation mode, the contactless card reader acts as an active device and generates an electromagnetic field, and the mobile terminal acts as a passive device, emulates a contactless card, and interacts with the contactless card reader. In the card reader mode, the mobile terminal acts as an active device and emulates a contactless card reader to generate an electromagnetic field, and the contactless IC card acts as a passive device and interacts with the mobile terminal, wherein the mobile terminal has functions of a contactless IC card reader complying with the ISO14443, or ISO15693, or Felica standard, and is able to read an external contactless IC card using the same standard. In the point to point mode, either of two working mobile terminals can act as an active device or passive device respectively to carry out point to point data transmission.
The default working mode of the mobile terminal is the card emulation mode, in which the radio frequency of the NFC emulation front end chip is in the working state, and when the mobile terminal enters into the working area of a contactless card reader, the mobile terminal can detect the signal transmitted by the contactless card reader, and set up communication with the contactless card reader. Besides, when the mobile terminal is power on, the NFC emulation front end chip uses the power provided by the mobile terminal to interact with the contactless card reader.
If the contactless card reader application on the mobile terminal is run, the contactless card reader application can make the NFC emulation front end chip work in the card reader mode by relative instructions, and after the contactless card reader application ends, the NFC emulation front end chip returns to the card emulation mode. If the point to point communication application on the mobile terminal is run, the point to point communication application can make the NFC emulation front end chip work in the point to point mode by relative instructions, and after the point to point communication application ends, the NFC emulation front end chip returns to the card emulation mode. Therefore, after the mobile terminal is powered on, the NFC emulation front end chip is in the card emulation mode in most of the time.
In order to implement contactless electronic payment in the card emulation mode, the mobile user card is required to support the SWP, and the mobile user card communicates and connects with the NFC emulation front end chip in the physical layer and the data layer by using the SWP, of which the specific implementation can be seen in related existing technical schemes. The mobile user card and the NFC emulation front end chip interact in the logical control layer by using the Host Controller Interface (HCI) protocol, which specifies the interaction process of the mobile user card and NFC emulation front end chip when implementing the contactless electronic payment in the card emulation mode, and the specific implementation can be seen in related existing technical schemes.
It can be seen from the above description that the mobile user card is required to support the SWP so as to implement the contactless electronic payment in the card emulation mode. If the mobile user card employed in the mobile terminal does not support the SWP, the mobile terminal is unable to emulate a contactless card; however, the NFC emulation front end chip in the mobile terminal is still working in the card emulation mode. As the radio frequency of the NFC emulation front end chip is in the enabled state, it will consume the power of the mobile terminal. Besides, when the mobile terminal enters into the working area of a contactless card reader, the NFC emulation front end chip will still respond to the signal transmitted by the contactless card reader, and execute the process relating to setting up communication; but if the mobile user card does not support the SWP, it is unnecessary to respond to the signal of the contactless card reader at all, and thus such response of the NFC emulation front end chip to the signal of the contactless card reader causes a waste of resources.